Physical activity has long been recognized as an important component of cancer prevention. Given the precipitous drop in activity during childhood, preventing this reduction in activity is a key point of emphasis. To this end, children's non-discretionary time at school provides an ideal target of intervention, with physically active lessons identified as a useful strategy. Because teachers are asked to implement these interventions, we must know more about outcomes that are in-line with teacher motivation. As such, this proposal is designed to determine the impact of physically active lessons on in-school physical activity that occurs outside of recess and PE, along with both proximal (1 week) and distal (6 month) academic outcomes. To achieve these aims, 30 schools will be recruited in two waves and assigned to one of three groups: (1) experimental, (2) sedentary control, or (3) active, unrelated content control. If successful, these data will do much to advance teacher motivation to implement this and similar physical activity interventions, which, in turn, will help children to amass the recommended 60 min of daily physical activity that has been tied to greater lifelong activity and cancer prevention. PUBLIC HEALTH RELEVANCE: Objections have been raised to the use of in-school physical activity interventions as they interfere with academic instruction. The proposed study can overcome this objection as it aims to demonstrate academic benefits along with increased physical activity during an in-class physical activity intervention. Integrating physical activity with academic content has the potential to remove barriers to implementation and, as a result, contribute to life-long activity and the prevention of cancer.